1. Field of the Invention
The present invention relates to a press roll apparatus for pressing two glass sheets toward each other with an intermediate film sandwiched as an adhesive layer therebetween, so that the glass sheets can be temporarily bonded to each other by the intermediary film.
2. Description of the Relevant Art
Laminated glass for use as automobile front windshields is manufactured by a press roll apparatus which presses two glass sheets toward each other with an intermediate film as of polyvinyl butyral sandwiched therebetween, thus temporarily bonding the two glass sheets After the two glass sheets are temporarily bonded to each other, they are finally bonded in an autoclave.
One known press roll apparatus is disclosed in U.S. Pat. No. 4,696,713 (corresponding to Japanese laid-open patent publication No. 63-65624).
The disclosed press roll apparatus has a plurality of drive and free roll units that can independently move vertically, but fail to swing as a whole in directions perpendicular to the direction in which two glass sheets are inserted.
The free roll units have presser rolls which are swingable in directions normal to the direction in which two glass sheets are fed, so that the presser rolls can follow the shape of the glass sheets. The drive roll units also have presser rolls that are not swingable because of gears used to transmit drive power to the presser rolls Therefore, it has been difficult for the prior press roll apparatus to bond glass sheets of complex shape to each other.
The drive power is transmitted to only one of the presser rolls of each of the drive roll units to prevent undue forces from being imposed on the glass sheets as they are fed through the drive roll units However, the presser rolls of the drive roll units tend to slip against the glass sheets.